Actually I separated LCD and backlight completely. This is possible by removing the three screws that hold the piece of metal shielding the LCD logic board in place, then opening the assembly carefully and slipping out the lcd from the backlight frame.

I checked the connectors carefully for damage, both the LVDS cable that connects the whole display unit to the imac logic board, and the several "strips" that connect the actual LCD glass to its logic board. Again, there is no physical damage or loose connection that I can notice (checked with lens and light to make sure).

There is one thing that I am not sure of: on the bottom side of the screen there are the connectors mentioned above that connect the lcd itself to its logic board. These are soldered and can not be removed. But on the side of the display there are four "free" connectors, which are attached to the glass but lead nowhere, they just sort of stick out. Do they need any special "treatment"?

3 Answers

From your pictures it looks like a TAB fault (Tape Automated Bonding). A TAB fault is caused by a connection failure from the TAB that connects the transparent electrode layers to the video driver board of an LCD. If you moved the LCD logic board in a manner other than gently opening it like a flap you more than likely have compromised the connections between it and the glass, the TAB. The wires in the TAB/ribbon cables that attach the logic board to the transparent electrode layer on the glass are about half the size of a strand of hair. They are very fragile and their exact placement is critical. If the TAB is broken you need to replace the LCD.

I tried to inspect the TAB wires with a magnifying glass, but this is definitely beyond my eye's resolution capability ;)

I will then try to get it repaired. Found a shop in Ireland that would ship a replacement display to my home for about 250 Euros, while Apple service quoted an approximate 3-400 Euros for the repair. I guess I will try to do it myself ;) No way am I going to pry open the display assembly again!!!

I've talked to several people at Apple on the screen problems and they are well aware of them but are keeping closed mouth about it for now. I'm pretty sure we will either see a class action suit against them shortly or they will fess up on their own. Regardless of what you end up doing, keep records to turn it for reimbursement.

As to trying to get back working let's see if we can isolate the problem. Hook it up to an external monitor and see if the problem persists. What did you use to clean it and how did you go about doing it?

I opened the display, ie separated LCD from led backlight, following instructions in the post I referred to in my original message, then just removed the dust with a microfiber cloth. No liquids involved.

I am familiar with that post. The instructional video has been deleted. This is part of my notes:.... 4 cables that attach the LCD panel to the boards. Remove them, but be very careful, especially with the wide flat cable that's close to the middle of the screen - it's very easy to damage that connector... The other thing that comes to mind is how wide did you open it? My understanding is it was best to open it as little as possible.If you opened it up to far you may have hurt the connections to the actual LCD.

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